Chlamydophila Infections (Psittacosis [Ornithosis], C Pneumoniae, & C Trachomatis)

Key Features

Essentials of Diagnosis

• Psittacosis

  • Fever, cough, malaise, chills, headache

  • Diffuse rales; no consolidation

  • Long-lasting radiographic findings of bronchopneumonia

  • Isolation of the organism or rising titer of complement fixing antibodies

  • Exposure to infected birds (ornithosis)

• Neonatal Chlamydophila (Chlamydia) conjunctivitis

  • Watery, mucopurulent, to blood tinged discharge and conjunctival injection presenting from a few days of life until 16 weeks of age

  • May be associated with neonatal Chlamydophila pneumonia

  • Identification of Chlamydophila conjunctivitis or pneumonia in a neonate should prompt evaluation and treatment of the mother and her sexual partner

General Considerations

• Chlamydophila psittaci

  • When the pathogen is transmitted to humans from psittacine birds (parrots, parakeets, cockatoos, and budgerigars), the disease is called psittacosis

  • However, other avian genera (eg, pigeons and turkeys) are common sources of infection in the United States, and the general term ornithosis often is used

  • Human-to-human spread rarely occurs

  • Incubation period is 5–14 days

• Chlamydophila pneumoniae (formerly Chlamydia pneumoniae)

  • May cause atypical pneumonia similar to that due to Mycoplasma pneumoniae

  • Transmission is by respiratory spread

  • Lower respiratory tract infection due to C pneumoniae is uncommon in infants and young children

  • Has been associated with acute chest syndrome in children with sickle cell disease

• Chlamydophila trachomatis

  • In infants born to infected mothers, infection can be acquired through exposure in the birth canal, causing neonatal conjunctivitis and pneumonia

  • Risk of acquisition for a baby born vaginally to an infected mother is about 50%

  • "Trachoma"

    • Caused by certain C trachomatis serovars (A–C)

    • Seen in developing countries in Africa, Asia, Latin America, the Middle East, and some Pacific and East Pacific islands; rare in the United States

    • Most common cause of acquired blindness worldwide

    • Peak incidence is seen at 4–6 years of age, with scarring and blindness occurring in adulthood

Clinical Findings

Symptoms and Signs

• C psittaci pneumonia

  • Tends to be mild in children

  • Onset is rapid or insidious, with fever, chills, headache, backache, malaise, myalgia, and dry cough

  • Pneumonitis, altered percussion notes and breathe sounds, and rales

  • Pulmonary findings may be absent early

  • Dyspnea and cyanosis may occur later

  • Splenomegaly, epistaxis, prostration, and meningismus are occasionally seen

  • Delirium, constipation or diarrhea, and abdominal distress may occur

• C pneumoniae pneumonia

  • Clinically similar to M pneumoniae infection

  • Most patients have mild upper respiratory infections

  • Lower respiratory tract infection is characterized by

    • Fever

    • Sore throat (perhaps more severe with C pneumoniae)

    • Cough

    • Bilateral pulmonary findings and infiltrates

• C trachomatis neonatal conjunctivitis and pneumonia

  • Can occur from a few days until 12–16 weeks after birth

  • Mild to moderate swelling of the lids and watery or mucopurulent discharge may be present

  • Conjunctivae may be friable and there may be some bloody discharge

  • Pneumonia may occur in babies with or without neonatal conjunctivitis

    • Most commonly seen between 2 and 12 weeks of age

    • Most babies are afebrile and have tachypnea ...